Structure-function analysis of the inositol trisphosphate receptor - - PDF document

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Sep 10, 2022 182 likes •271 views

Structure-function analysis of the inositol trisphosphate receptor and its role in cell life and cell death Jan B. Parys School of Medicine K.U.Leuven INTRACELLULAR Ca 2+ SIGNALING (Clapham, 1995) 1 IP 3 R activation (Berridge, 2008) IP 3

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Structure-function analysis of the inositol trisphosphate receptor and its role in cell life and cell death

Jan B. Parys School of Medicine K.U.Leuven

(Clapham, 1995)

INTRACELLULAR Ca2+ SIGNALING

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2 (Berridge, 2008)

IP3R activation IP3R regulation and function

Isoform diversity (expression, localization, properties)

Our research group, last 20 years: > 300 papers

Regulation by Ca2+, ATP, … Regulation by regulatory proteins (CaM, IRBIT, …) Regulation by phosphorylation (PKC, MAPK, Plk1, …) Function

ocyte maturation/fertilisation,

cancer, cell death, …

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1) Regulation of IP3R by protein kinases and phosphatases 2) Role of IP3R activity during apoptosis and autophagy 3) Role of the interaction between IP3R, polycystin-1 and -2 in autosomal dominant polycystic kidney disease 4) Regulation of connexin and pannexin hemichannels

ONGOING RESEARCH PROJECTS

RECENT PUBLICATIONS (selection) Szado et al. (2008). Phosphorylation of inositol 1,4,5-trisphosphate receptors by protein kinase B/Akt inhibits Ca2+ release and apoptosis. Proc. Nat. Ac. Sci. USA 105, 2427-2432. Rong et al. (2008). Targeting Bcl-2-IP3 receptor interaction to reverse Bcl-2's inhibition of apoptotic calcium signals. Mol. Cell 31, 255-265. Ito et al. (2008). Inositol 1,4,5-trisphosphate receptor 1, a widespread Ca2+ channel, is a novel substrate of polo-like kinase 1 in eggs. Dev. Biol. 320, 402-413. Vanderheyden et al., (2009). Regulation of inositol 1,4,5-trisphosphate-induced Ca2+ release by reversible phosphorylation and dephosphorylation. Biochim. Biophys. Acta 1793, 959-970. Vanderheyden et al. (2009) Regulation of inositol 1,4,5-trisphosphate receptor type 1 function during oocyte maturation by MPM-2 phosphorylation. Cell Calcium 46, 56- 64. de Mattia et al. (2009). Human golgi antiapoptotic protein modulates intracellular calcium

fluxes. Mol. Biol. Cell 20, 3638-3645.

Rong et al. (2009). The BH4 domain of Bcl-2 inhibits ER calcium release and apoptosis by binding the regulatory and coupling domain of the IP3 receptor. Proc. Nat. Ac.

Sci. USA 106, 14397-14402.

Lee et al. (2009) Inositol 1,4,5-trisphophate receptor 1 degradation in mouse eggs and impact on [Ca2+]i oscillations. J. Cell. Physiol. (in press). Sammels et al. (2009). Polycystin-2 activation by IP3-induced Ca2+ release requires its direct association with the inositol 1,4,5-trisphosphate receptor in a signalling

microdomain. FASEB J. (submitted).

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UNIVERSIDAD DE CHILE Calcium Signaling : C. Hidalgo and E. Jaimovich Cell death: S. Lavandero and A. Stutzin Unfolded protein response: C. Hetz Pontificia Universidad Católica de Chile Connexins: JC. Saez Ca2+ signals regulate both cell death and survival

(adapted from Rong and Distelhorst, 2008)

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The anti-apoptotic protein Bcl-2

Bcl-2 / Bcl-XL Bax / Bak (adapted from Reed, 1998)

1 239

+ 20 μg/ml anti-CD3

Bcl-2 inhibits Ca2+ signals in Jurkat cells

Expression of Bcl-2 Actin control

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Bcl-2 from Jurkat cell extracts interacts with IP3R1

IP

contr. anti-

IgG IP3R1 Bcl-2 Input

GST + domain 1 2 3 4 5 6

Pep1: MDENSPLMYHIHLVELLAVC Pep2: NVYTEIKCNSLLPLDDIVRV Ctrl: DLNEVTCSLIVDRINPVKLY

Bcl-2 interacts with a unique site in the regulatory region of IP3R1

IP anti- anti-

contr. anti-

IP3R1 IP3R1 IgG IP3R1 + + Ctrl Pep2 Bcl-2 Input

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The BH4 domain is responsible for IP3R1 interaction

Fractional loss (%/2 min) Time (min)

IP3 no addition + BH4 + Pep2 + 60 μM contr. + 40 μM BH4

[Peptide] (μM) IP3-induced Ca2+ release (%)

contr. BH4

The anti-apoptotic proteins Bcl-2 and Bcl-Xl interact

with the IP3R.

These interactions participate in the pro-survival

response.

The BH4 domain of Bcl-2 interacts with part of the

regulatory domain of the IP3R and this interaction decreases IP3-induced Ca2+ release.

Specific disruption of the interaction leads to increased

IP3-induced Ca2+ release.

It is our working hypothesis that targeted disruption of

the interaction can lead to controlled apoptosis, e.g. during abnormal cell proliferation (cancer).

Bax-inhibitor-1 and Beclin-1 also interact with both

IP3Rs and Bcl-2 (not shown). CONCLUSIONS

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